The point of departure is when Sulayman 1 does not kill his most be able son who succeeds in as Sulayman the second, Suleyman 2 stops expanding into Europe, keeping the Ottoman Empire at its territorial height and keepig the military in one piece with mo defeat at Vienna. The Ottomans then enter a period of isolation and economic, industrial, and economical buildup as well as builing a up its infrastructure.
This allows the empire to survive much longer and eventualy become a major player in the global theater